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FEP Categories

FEPs are classified along three independent dimensions: Topic, Protocol, and Type. A single FEP may have multiple topic and protocol tags.

Topic

Describes the functional area a FEP addresses.

Topic Description
Identity & Authentication Public keys, signatures, integrity proofs, DIDs, WebFinger resolution, OAuth -- establishing and verifying identity
Content & Objects Object types, media attachments, formatting (MathML, MFM), quotes, metadata, licensing -- the data that travels across the network
Collections & Filtering Managing, sorting, filtering, and observing collections -- from Blocked Collection to TREE-based filtering
Conversations & Messaging Threads, context property, replies, Conversation Containers, backfilling -- how conversations are structured and retrieved
Discovery & Capabilities NodeInfo, capability discovery, DNS resolution, Activity Intents -- "what can you do and how do I find you"
Federation & Delivery Delivery mechanisms (multibox, relays), visibility, follower sync, error handling -- the S2S transport layer
Governance & Process The FEP process itself, namespaces, conformance tests, SWICG decisions -- meta-level concerns
Interoperability & Protocols Bridges to other protocols, URL schemes, Proxy Objects, FEDERATION.md -- interaction with external systems
Social Features Reactions, polls, events, marketplace, to-dos, payments -- domain-specific functionality
Migration & Portability Account migration, Move activity, export formats, portable objects -- moving data between servers

Protocol

Describes which ActivityPub protocol layer a FEP operates on.

Protocol Description
S2S Server-to-Server -- defines activities or behavior exchanged between federated servers via inbox delivery
C2S Client-to-Server -- defines interactions where a client posts to an outbox or queries server endpoints

A FEP may specify both S2S and C2S if it covers both layers. FEPs that only define data models, vocabularies, or process conventions do not carry a protocol tag.

Type

The existing type field in FEP frontmatter. Describes the intent of the document.

Type Description
implementation Defines a concrete specification that software can implement and test for conformance
informational Provides guidance, documents existing practice, or describes process -- no conformance requirement